What Causes Your Sodium Levels to Drop?

Sodium usually has a negative connotation to it, but in actuality, sodium is necessary for many functions of your body. Low sodium levels may be a sign of dehydration or organ failure. The condition in which your blood level of sodium is abnormally low is called hyponatremia. If you feel your sodium level has dropped below the normal level you should contact your doctor to see if you have an underlying cause that may need to be treated.

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Function of Sodium

Sodium plays a key role in your body function. It helps to maintain normal blood pressure, regulate your body's fluid balance, support the work of your muscles and nerves and maintain normal blood pressure. Sodium is an electrolyte that helps to regulate water levels in your cells. According to MayoClinic.com, normal blood plasma contains between 136 and 145 milliequivalents per liter (mEq/L) of sodium. When your sodium level falls below 135 mEq/L, hyponatremia occurs.

Symptoms of Low Sodium Level

Symptoms that you may have a low sodium level include headache, confusion, nausea, vomiting, fatigue, appetite loss, muscle weakness, seizures and decreased consciousness or coma.

Low Sodium Due to Exercise and Diet

If your water and sodium levels are both low, it is known as hypovolemic hyponatremia. This may happen when you exercise due to sodium loss in your sweat. Drinking too much water during exercise may dilute the sodium content in your blood. Dehydration causes your body to lose fluids and electrolytes, which may reduce your sodium level. A diet low in sodium and high in water may disturb the balance between sodium and fluids in your blood. This also may occur if you have taken an excessive amount of diuretics.

Low Sodium Due to Organ Failure

The imbalance between sodium and water in your blood is called hypervolemic hyponatremia. Hypervolemic hyponatremia is when your body retains excess water and dilutes the sodium concentration. This can occur if you have hypothyroidism, cirrhosis, a liver disease that may cause fluids to accumulate in your body; kidney failure or other kidney diseases reducing the ability of your body to remove excess fluids; or congestive heart failure which causes your lower extremities and abdomen to retain fluids.

Low Sodium Due to Medications or Severe Vomiting or Diarrhea

Some antidepressants and pain medications may cause you to urinate or perspire more than normal. This may cause your sodium levels to drop. Severe vomiting or diarrhea may cause also your body to lose fluids and electrolytes, such as sodium.


Treatment to raise your sodium level may be as easy as changing the medication you are taking that affects your blood-sodium levels; decreasing the amount of water you drink or increasing the amount of salt in your diet. You should contact your doctor before making any changes to your normal routine.

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